Despite this evidence, his theory was initially rejected due to lack of explanation for how continents could move over the earth. However in 1948 a survey of the ocean floor found a ridge running north to south beneath the Atlantic Ocean. During the 1950's magnetic surveys of the ocean floor showed regular patterns of palaeomagnetic striping about the ridges. When lava erupts, iron rich minerals within it are aligned with the earth's magnetic field, this is fixed as the lava cools and they record the earth's polarity at the time they cool.

Whereas seismicity is where the build up of pressure in the crust is released. Both volcanic and seismic activty when plotted on a map can be seen to follow certain patterns and it is this distribution that helps explain the plate theory. The distributions of earthquake events are found in broad, uneven belts around plate margins and it is the movement of the plates that cause the seismic events. Most of these earthquakes occur along destructive margins, where the heavier oceanic crust descends underneath continental crust. A build up of pressure here, where no subduction takes place for a space of time, eventually leads to a large slippage of the oceanic plate causing shockwaves

The magma formed from oceanic crust is less dense than (due to its high water content) the mantel and rises up through the vent (this can be seen in figure 1). The lava is generally acidic and is also viscous. This means that eruptions are usually, violent and unpredictable. At divergent plate boundaries the eruptions are from a crack. The eruptions are intermittent and not very violent as the lava has a low viscosity and acidity. Hot spots are volcanic regions where the underlying mantle is thought to have a higher temperature than the surrounding magma allowing it to rise up, hot spots may form island chains are arcs.

Therefore most Cholera outbreaks occur in spring and autumn when ocean surface temperatures and algae blooms are at their highest. More algae mean more Copepods, and more Copepods mean more Cholera bacteria. The map on the left shows that the areas that Cholera is discovered in are situated below the Brandt line. This is because these areas are surrounded by warm oceans where the growth of algae will be high. Therefore the Cholera bacteria will occur in higher frequency in these areas. This is proven by the map of the world below, which shows the temperatures of the world's oceans.

The eruptions of Soufriere Hills beginning in 1995 affected Montserrat's rich and poor inhabitants. As the mostly uninhabitable island's capital town Plymouth was covered in ash, lahars, and pyroclastic flows, many people were evacuated and the majority of the island's homes were destroyed, displacing 7000 people. As a British territory, residents were offered the chance to move to the UK, and similar offers were made from the US; but for the poorest people with little money this would have resulted in an even worse situation- and as Montserrat is formally classed as an LEDC this was the majority of the population- the GNI per capita is only $3,400.

Floods happen when prolonged rain, intense storms, or meting snow release more water than rivers or land can contain, without causing damage, as a result they over-flow their banks, usually into low lying surrounding areas. More than one third of deaths caused by natural disasters are from serious cases of flooding. Some areas are more prone to flooding than others. For example; melt waters that originate in the mountainous regions of its neighbours India and Nepal regularly inundate the relatively low-lying nation of Bangladesh.

Volcanic processes also can be found on or near subduction zones associated with destructive plate margins. The line of volcanoes, or 'ring of fire' that surrounds the Pacific Ocean is associated with plate subduction. This tends to be the most violent of all activity, potentially explosive, where it can be hazardous to the public. As do the types of hazards, which are categorised into primary and secondary. Primary hazards, created by the direct vulcanicity of the volcanoes, could include tephra, pyroclastic flows & volcanic gases.

The primary earthquake hazard directly responsible for mortality is surface seismic waves which cause ground shaking. This poses a huge hazard as buildings and other structures collapse, killing or injuring their occupants. This was the case in Sichuan, China in 2008 where severe ground shaking was the direct cause of death, injury and the catastrophic destruction of hospitals, roads and other infrastructure. An estimated 5.4 million buildings collapsed and a further 21 million were damaged. In poorer areas such as rural China, buildings are compromised despite strict regulations due to poor quality construction work and corruption meaning the correct materials is not used.

Predict is defined as:-The skill of explaining new events based on observations or information. According to: - www.dpi.state.wi.us/standards/sciglos.html When looking at the different types of hazards to injure or kill people, or costing the most economic price, we consider such hazards as tsunamis and earthquakes. Recently, In December's tsunami in the Indian Ocean, an estimated 250,000-300,000 people were killed or are still missing, while millions of lives have been upturned, socially and economically, by its impact. A main reason for the huge death toll and such high economic damage was that the tsunami hadn't been predicted, and the people were not aware of its presence under the Indian Ocean.

People were not put into temporary accommodation for up to two weeks after the event because the Japanese government originally refused assistance from foreign countries to help with the aid effort. The secondary effects of the earthquake like the gas leaks and fires killed 3000 people and many businesses were lost in the port. The Kobe earthquake shows that sometimes the wealthier countries can be just as badly affected. The Icelandic volcano, that caused the ash cloud, affected many people around the world, both wealthy and poor.

The final cause of droughts, is down to the human race, and their lifestyle demand for extra water to fulfil their needs, this puts extra pressure on supplies. The great Drought of China during 1876-1879 was one of the deadliest droughts in the worlds recorded history; no food at all could be grown on 386,000 square miles of farmland across nine provinces of northern China. Rivers were dry, so most crops and livestock died. An estimated nine million people died.

Where as due to the change of climate, fertile land turns into desert. However, you could argue that although climate change is thought to be a part of the earth's natural cycle, human actions are said to fasten its process leading to the effects that it has. Moreover, desertification leads to not only famine and the threat of food security. Due to the land turning into desert, the growth of crops is unsustainable which leads to many people whom rely on the growth of crops for their personal food source to starve. This begins famine. Famine sees the struggle to receive food and a long suffering demonstrating here of both social and environmental factors.

* A Semi-Molten Outer - core contains a solid inner core with a temperature of 6,000°C. * The Mantle - (it surrounds the core) this is largely composed of silicate rocks rich in iron and magnesium. Apart from the more rigid upper mantle, most of the mantle (asthenosphere) is semi-molten, with temperatures near the core reaching 5,000°C. These high temperatures generate convention currents. * The Crust - (the thinnest layer) this has the coolest, least dense rocks. These rocks are high in silicon, oxygen, aluminium, potassium & sodium. There are two types of crust: oceanic crust, mainly basaltic in nature and around 6-10km thick, and continental crust, which is composed of a widely variety of igneous, metamorphic & sedimentary rocks.

They commonly hit areas on the East Coast of Luzon due to the often high winds and storm surges. In the tropical cyclone season, June to November, there are on average 7 destructive cyclones per year causing 529 deaths and $68 million dollars in damage. Heavily related to typhoons are floods, the Philippines has an average annual precipitation level of 2083mm due to the heavy rain associated with typhoon season. Take for example, Manila, the capital of Luzon is especially vulnerable due to its steep relief from mountain areas, can cause flash flooding which in turn creates the problem of rapid surface run-off which can have a devastating effect in a matter of minutes.

2 Affected by disasters 1975 - 2004 Fig.2 shows the proportion of people worldwide affected by disasters by country. The map of countries most vulnerable to natural hazards is a rather different picture; the two most vulnerable countries are India and China which also, as seen in fig.3, have the highest population densities. Africa, whose population is relatively less dense, is not as severely affected by hazards of a similar magnitude. The most severely affected populations in general are in Southern and Eastern Asia, which sit deep in the junction between the Eurasian, Pacific, and Indo-Australian plates.

The Philippines is a Newly Industrialised Country (NIC) and has low to middle income of US$5000 per capita. Their economy is mostly dependant on agriculture (because of the rich, fertile soils on the volcanic hills), manufacturing and tourism, which are all at the mercy of natural disasters. Although it is only a small group of islands, the population is huge at 91 million (over twice the size of California's) and has an average population density of 306.6/km2. Most of the population have a very low income and live in the more vulnerable areas along the coast, or farm on volcanic mountains.

This means they possess the knowledge, expertise and financial support to plan, predict (to some extent!) and prepare for natural hazards. In Kobe, every building is subject to stringent specifications designed to be earthquake proof and important city landmarks, Kansai International Airport and Akashi Suspension Bridge, were built using high-tech construction materials. Government departments are responsible for managing and coordinating emergency responses and educating the public about natural hazards. As a result, the city holds regular earthquake drills in public places and emergency services practice through simulations. Although in MEDC's, the higher level of development and infrastructure means the total cost of the hazard is usually higher, the total economic cost of Kobe's earthquake was believed to be around $100 billion US dollars, 2.5% of Japan's GDP at the time.

The local governments in LA are have an assertive stance concerning the legislation of new buildings and developments. The structures have to be designed to withstand earthquakes (in particular high-rise buildings). In order to take action in the aftermath of a quake, the government is well prepared in terms of action plans. Gas, water, and electricity pipelines and cables have to pass extremely demanding safety measures in order to reduce damage to people and the L.A area in the case of a quake. Tsunamis Tsunamis are extremely large tidal waves which are triggered by earthquakes under the sea (submarine earthquakes).

However, as plates move apart (diverge) new oceanic crust is formed. Both convergent and divergent plate margins are vital, and the unique movements of both margins have resulted in the formation of global structures, including Ocean Ridges, Ocean trenches, Rift Valleys and Mountain ranges. At divergent plate margins where plates move apart, 2 main global structures are formed. The type and nature of these structures are determined by the location of the divergent plates. Where plates move apart in oceanic areas, an 'oceanic ridge' is likely to be formed.

On the other hand both densely/sparsely populated LEDCs lack the infrastructure and facilities to cope with such a disaster and as a result tend to have an extremely high number of fatalities, as recently seen in Chile, Haiti and the Indian Ocean Earthquakes tsunamis. On 26th of December 2004 an underwater 'megathrust' earthquake measuring 9.3 on the Richter scale (the second largest earthquake ever recorded) occurred off the northern coast of Sumatra, Indonesia. The central cause of this was due to the sudden release of pressure during the collision of the Indo-Australian plate (moving NE 6cm/year)

The desert is growing outwards there are quite a few countries under threat from desertification and every year thanks to global warming the Sahel is growing. This is the first idea and I tend to agree with his because as the planet warms up the arid regions are going to spread outwards and more and more of the country will be covered. The second idea suggests that there are pockets of degradation around areas of human activity and as the land becomes over cultivated and over grazed it starts to turn into

The information provided by the Met Office to the Environment Agency will be used to consider flood risk management strategies for the Thames Estuary up to 2100. The Thames Estuary 2100 (TE2100) is a project which "aims to determine the appropriate level of flood protection needed for London and the Thames Estuary for the next 100 years." London's existing flood defences will only provide protection up until 2030.

Conclusion analysis

Good conclusions usually refer back to the question or title and address it directly - for example by using key words from the title.
How well do you think these conclusions address the title or question? Answering these questions should help you find out.

Do they use key words from the title or question?

Do they answer the question directly?

Can you work out the question or title just by reading the conclusion?

"In conclusion I believe that the statement 'volcanoes are more dangerous hazards than earthquakes' to generally be false. Although earthquakes can be prepared for a lot better than volcano eruptions, earthquakes are less easy to predict and cause a substantial amount more damage. Earthquakes are also more frequent and usually affect a larger area and can also cause tsunamis, floods, fires, landslides and the liquefaction of soil.
Iden Ranapour
1"

"To conclude, the key spatial and temporal factors listed above leads me to believe that the extent to which earthquakes represent hazards DOES depend on where and when they are experienced. In particular, 'where' factors such as level of development and rural-urban disparities as well as 'when' factors such as time of day and time between hazards are crucial in determining the extent of damage caused by an earthquake. However every earthquake is different and it is only when a combination of the above elements come together does an earthquake become a real hazard. After all, it is estimated that over 1,400,000 earthquakes occur annually with only up to 100 of those deemed to be potentially hazardous."

"Both hazards are deadly and ruin both property and human life; however volcanoes in my opinion are more dangerous than earthquakes. Earthquakes although cannot be predicted can be protected against saving thousands of lives. Volcanoes although can be predicted cannot be defended against, even if towns are evacuated they are still destroyed creating huge humanitarian and economic problems. Accurate volcano prediction if in place isn't always linked up with towns in danger; this makes the prediction useless anyway. Finally Volcanoes also have lasting implications; their secondary effects such as lahars can be felt for generations."